Trailing 2-1 in their playoff series against the Indiana Pacers and already without Giannis Antetokounmpo, the Milwaukee Bucks are also facing the possibility of not having Damian Lillard for Game 4 on Sunday.

Per Chris Haynes of the NBA on TNT, Lillard will be listed as doubtful after being diagnosed with a Grade 1 Achilles strain suffered in Game 3.

Shams Charania of The Athletic and Stadium added Lillard is in a walking boot and there is "serious doubt" about his availability for Sunday. Charania also noted that Lillard has "played through significant soreness" in his Achilles before reaggravating it on Friday night.

Lillard appeared to injure his leg late in the first quarter of Game 3 when Pascal Siakam landed on his heel/ankle attempting to contest a layup.

After limping off the court and being removed for the remainder of the quarter, Lillard returned to the game 22 seconds into the second quarter.

Lillard told reporters after the game he aggravated an Achilles injury that has been bothering him since the regular-season finale in the fourth quarter, but he wanted to remain on the floor to help the team:

"I just wanted to be on the floor in case opportunity came up or however I could help. We're gonna get back and just have to get ahead of it because that's not something that you want to play with. It's one of those spots on your body where you literally can't, you can't do nothing about it. If you can't move you can't move. We have a couple of days to start and try to get ahead of it. Get it feeling better and get ready for Sunday."

Despite finishing with 28 points, Lillard had his least efficient game of the series. He went 6-of-20 overall, made just four of his 12 shots from behind the arc and didn't score or attempt a field goal in overtime.

The Bucks lost 121-118 in Game 3 when Tyrese Haliburton converted a three-point play with 1.1 seconds remaining in the overtime period.

Antetokounmpo hasn't played since suffering a strained left calf against the Boston Celtics on April 9. The two-time NBA MVP's status for Game 4 has not yet been revealed,

Head coach Doc Rivers said Thursday that Antetokounmpo was "getting close" before acknowledging he's not sure exactly what that means given the nature of the injury.

"He's getting close," Rivers said. "But, I don't know what that even means. I'm being honest. I saw him moving around and in my mind I said he's getting close. Does that mean a day, four days? I'm not sure."

If Bucks fans want to be optimistic about Lillard's status, Khris Middleton was listed as doubtful prior to Game 3 with an ankle injury. The three-time All-Star wound up playing 41 minutes, scoring 42 points and grabbing 10 rebounds.

The Bucks need a win in Game 4 at Gainbridge Fieldhouse to avoid falling into a 3-1 hole and facing an elimination game in their home arena for the second straight year.

Game 4 between the Bucks and Pacers tips off on Sunday at 7 p.m. ET.